The present invention relates to decorative light strings such as Christmas tree lights and the like having an improved interlock between the lampholders and their associated sockets within the string.
Decorative miniature lights such as miniature Christmas lights are assembled into light strings and, the typical arrangement has the lights connected in a series circuit. A series of lamps are disposed within individual lampholders which are then inserted within complementary electrical sockets. The lampholders must be securely retained within the socket in order for the serially connected decorative light string to remain operative.
A common problem associated with serially connected string sets is the failure of the light string when one of the individual lampholders comes loose or is removed from its electrical socket during handling or use. Each lampholder is normally configured to be received telescopically within an elongate lamp base or socket with the socket and the lampholder secured to each other by a friction fit connection. This typical arrangement can render the light string susceptible to failure because the aforementioned friction fit has generally been inadequate and predisposes the lampholder to becoming loosened from its corresponding electrical socket.
Attempts have been made to further secure the lampholder within its electrical socket. In one arrangement, the lampholder and its corresponding socket include a lug and locking element combination. The lug is positioned on the socket member and the locking element extends from the lampholder with a living hinge connecting a free end portion to the housing on the lampholder. An aperture in the free end portion receives a portion of the lug to form a positive interlock between the lug and the locking element. The living hinge, however, represents a weak point in the interlock. Additionally, the interlock between the locking element and the lug can be difficult to manually operate due to the small sizes of those elements.
In another approach, a separate clamping member fits over the lampholder and frictionally engages a structure on the outer housing of the electrical socket member to retain the lampholder within the socket. The requirement for an additional separate locking piece for each lamp/socket combination, however, increases manufacturing expenses as well as the final price of the string set. Additionally, the clamping device for individual lamp/socket combinations can be lost or broken and thereby render those individual lamp/socket pairs without a retention mechanism.
Accordingly, it is an object of the present invention to provide an improved interlock for light strings such as miniature lights, for example.
Another object is to provide an improved interlock which is integral with the lampholder and/or the electrical socket member.
Another object is to provide an improved interlock which is of a fairly rigid and strong construction while permitting same flexure during the interlocking of parts.
These and other objects of the invention will be apparent to those skilled in the art on a closer examination of the remainder of the disclosure including the summary of the invention, the detailed description of the preferred embodiments and the appended claims.